Refractory brick and furnace construction



May 24, 1966 H. N. HALL 3,252,436

REFRACTORY BRICK AND FURNACE CONSTRUCTION Filed Aug. 5, 1964 2 Sheets-Sheet l lNVENTOR HORACE N. HALL ATTORNEYS May 24, 1966 H. N. HALL REFRACTORY BRICK AND FURNACE CONSTRUCTION i Filed Aug. 5, 1964 2 Sheets-Sheet 2 ooi O1 o9 l NVE NTO R HORACE N. HALL ATTOR NEYS United States Patent O 3,252,436 REFRACTRY BRICK AND FURNACE CNSTRUCTION Horace N. Hall, Collegeville, Pa., assigner to E. J. Lavino and Company, Philadelphia, Pa., a corporation of Delaware Filed Aug. 3, 1964, Ser. No. 387,115 l Claims. (Cl. 11G-99) The present invention relates to refractory brick units, and more particularly to refractory brick units which are adapted to be employed in open hearth roofs.

The present invention represents an improvement over U.S. Patent No. 3,139,048 wherein a refractory brick unit and furnace construction is illustrated which incorporates a construction to minimize the problem of spalling. The present invention employs the same concept as this patented arrangement in that the cold end of the refractory body is substantially square and within certain predetermined critical dimensions while the hot end face of the refractory body is out of `square and also within certain predetermined dimensions. This substantially square cross section has proved to successfully alleviate spalling and is employed for such purpose in the present invention.

In the aforementioned patent, the refractory brick unit is provided with a steel plate on all four faces of the unit. It was felt that metal to metal contact was necessary in order to obtain the desired results. In contrast to this arrangement of the patented refractory brick, the present invention incorporates a construction wherein the individual refractory brick units are provided with steel plating means on only two adjacent faces of the brick. This of course reduces the cost of the brick and it has been found that with this arrangement, it is possible to obtain the desired impervious solid rigid shell construction associated with each of the bricks of the roof'in the patented arrangement and that when the furnace has been fired, the bricks of the present invention will be reinforced against downward spalling. The steel plating means on two adjacent faces of the brick is illustrated and described as comprising two separte plates, but it will be apparent that this steel plating means may also comprise a single integral plate means of substantially L-shaped cross-sectional coniiguration which may be suitably secured on the brick adjacent the two said faces of the brick.

In the arrangement shown in the aforementioned patent, embossment means are provided on the plate attached to a lateral face ofthe brick and adjacent the hot end arris of the associated face.. In contrast to this arrangement, the present invention incorporates a unique construction wherein each of the plates on a particular refractory brick unit incorporates lirst embossment means adjacent the hot end arris of the associated face and second embossment means which is spaced from the first embossment means toward the cold end arris of the associated face. With this arrangement, the embossment means maintains the adjacent bricks in the assembled furnace roof in the proper spaced relationship to permit radial thermal expansion and end-to-end expansion relief.

The embossment means in the present invention preferably takes the form of a pluralityof integral outwardly extending embossments which may be of various shapes and which provide adequate strength to support the roof prior to tiring and yet which are adapted to collapse upon amaai Patented May 24, i966 ICC heating to provide for radial thermal expansion at both the hot and cold faces of the brick.

The embossments on the plate secured to the longitudinal face of each brick is arranged such that the first embossment means is spaced from the second embossment means a constant distance regardless of the length of the brick. With this arrangement, even though bricks of different length may be employed in the same roof, the upper set of embossments on each brick will be spaced the same distance above the lower set of embossments and the bearing between all of the bricks will be at a common location regardless of length.

The plate secured to the longitudinal face of each brick is also provided with an integral tab which is bent over and rests upon the cold end face of the brick so as to ensure that this plate will be retained in the proper operative position during initial ring of the brick. This integral tab will of course retain the plate in the proper spaced relationship on the associated face of the brick and will prevent it from dropping down between adjacent bricks after the adhesive substance has melted upon ring.

The plate secured to the lateral face of each brick is provided with one or more indentations, preferably two in number, which cooperate with spaced recesses formed in the lateral face of the brick. The indentations fit within the recesses so as to properly align this plate on the lateral face of the brick and to assure stability of the plate on such face.

While the tab means of the present invention provides a certain indication as to the proper alignment of the brick unit in a furnace roof, the cold end face of the brick unit is also provided with an indicating means in the form of an arrow or the like which indicates to a bricklayer the manner in which the brick is to be properly set into the roof.

An object of the present invention is to provide a new and novel refractory brick construction wherein the individual bricks are provided with light gauge steel plates on only two adjacent sides of each brick.

Another object of the invention is to provide a refractory brick and furnace construction wherein the steel plates are provided with integral embossments which are strong enough to support the roof prior to firing and which are adapted to collapse on heating to provide for radial thermal expansion as well as end-to-end expansion relief.

Yet another object of the invention is the provision of a refractory brick and furnace construction wherein the embossments formed on the plates of the brick are spaced in such a manner that `the bearing of adjacent bricks is at a common location regardless of the length of the individual bricks.

Still another object of the invention is to provide a refractory brick construction wherein one of the plates is provided with means for holding it .in proper operative position during initial tiring.

Still a further object of the invention is the provision of a refractory brick wherein the plate secured to the lateral face of the brick is provided with alignment means for aligning and stabilizing the plate on the lateral fac of the brick.

A still further object of the present invention is the provision of a refractory brick including means on the cold end face thereof for indicating the key direction to permit rapid orientation of the brick in a roof ring.

Other objects and many attendant advantages of the invention Will become more apparent when considered in connection with the specification and accompanying drawings, wherein:

FIG. l is a top perspective view partly broken away illustrating a portion of the roof of a conventional open hearth furnace;

FIG. 2 is a bottom view broken away of the assembled roof looking from the interior of the furnace prior to the initial firing of the furnace;

FIG. 3 is a top perspective view of a refractory brick unit -according to the present invention;

FIG. 4 is an enlarged sectional view partly broken away and taken substantially along line -4-4 of FIG. 3 looking the direction of the arrows;

FIG. 5 is a vertical section through the brick shown in FIG. 3 and taken substantially along line 5-5 0f FIG. 3 looking in the direction of the arrows;

FIG. 6 is a vertical section through the brick shown in FIG. 3 and taken substantially along line 6--6 of FIG. 3 looking in the direction of the arrows;

FIG. 7 -is a sectional view taken through two adjacent bricks of the roof shown in FIG. 1 wherein the adjacent bricks are of different length; and

FIG. 8 is a view illustrating a modified form of ernbossment means formed on the plates of the refractory brick unit.

Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, there is shown in FIG. l a portion of a roof of an open hearth furnace wherein one of the conventional skews formed bya row of bricks is indicated by reference numeral 10, it being understood that a plurality of the refractory units according to the present invention are disposed in side-by-side relationship to form an arch between skew 10 and a similar skew formed at the other side of the furnace. The arrow A indicates the lateral dimension of the roof or the width thereof while the arrow B indicates the longitudinal dimension of the roof or the length thereof.

A plurality of similar spaced support plates extend laterally of the roof and are inserted between adjacent rows of refractory `brick units in a known manner for supporting the roof of the furnace in operative position. These support plates are in turn supported by conventional jack means and beams as illustrated for example in the aforementioned patent.

As seen in FIG. l, a first pluarlity of laterally extending rows 22 of refractory brick units are shown as being disposed in side-.by-side relationship, and a second plurality of rows of refractorybrick units 24 of a greater height than the bricks in rows 22 is also illustrated. The intercooperation between these rows of different length bricks will be explained hereinafter. It will be understood that each of the refractory brick units includes a pair of opposite faces which face longitudinally of the furnace roof and a pair of opposite lateral faces which face laterally of the roof and that upon initial firing, the various rows of the units will be permanently fused to one another.

The construction of the individual refractory brick units can be best understood by reference to FIGS. 36 inclusive. As seen in these figures, each of the refractory brick runits includes a refractory body indicated generally by reference numeral 30, this body being made of magnesia and chromite. The :material of this brick is adapted to react with the steel casing to yield magnesioferrite which comprises the desired impervious solid rigid portion tending to prevent spalling of the bricks.

Body 30 includes a pair of opposite longitudinal faces 32 and 34 and a pair of opposite lateral faces 36 and 38. Each body also includes a cold end face 40 and an opposite hot end face 42 which is of course adapted to be disposed in facing relationship to the interior of the furnace when in assembled position.

The cold end face of the body is actually square and as illustrated in FIG. 5 may have a 3 inch dimension on each side. While this dimension has been chosen for the purpose of illustration, it is relatively critical and it is considered to be uneconomical to make the end face dimension of brick of less than a 3 x 3 dimension, and on the other hand, a larger end face dimension of 31/2 x 31/2" is considered to Ibe the maximum size which would generally be employed and still obtain the desired end result.

Each of the refractory brick units does taper slightly along the longitudinal faces thereof and as indicated in FIG. 5, the longitudinal faces may taper from a dimension of 3 inches at the cold end to a dimension of 2% inches at the hot end thereof. This amount of taper is necessary lin order to provide the desired keystone-shape which permits the units to be assembled so as to provide an arched roof.

A pair of metallic plates, preferably formed of steel or similar ferrous material is secured to two adjacent faces of the body of refractory material. A first plate r50 is secured to the longitudinal face 34, and a second plate 52 is secured to the lateral face 36. Each of these plates is adhesively secured to the associated faces by means of thin layers of adhesive material indicated by reference numerals 50 and `52' respectively. These thin layers of adhesive material are readily melted and ultimately destroyed .by the heat of the furnace when the furnace is fired. `It is apparent that the layers of adhesive material will retain the plates xedly upon the associated sides of the refractory brick until firing, Whereupon means hereinafter described is provided on the plates for retaining them in the proper position until the plates have reacted with the material of the brick to form the aforementioned impervious solid shell about the various bricks.

It will be noted that the lower edge 54 of plate 50 is spaced from the hot end arris 56 of the brick, while the opposite side edges 58 and 62 of the plate are spaced from the longitudinally extending arrises 60 of the brick. The upper edge 64 of plate 50 is also spaced below the cold end arris 66 of the brick.

The plate 50 also includes an integral tab portion which extends upwardly for a minor portion of its length as indicated by reference numeral 70 and then is bent over for the major portion of its length as indicated by reference numeral 72. This bent-over portion of the tab is disposed lin overlying relationship to the cold end face 40 of the refractory body. The tab serves to assist in indicating the alignment of the units and also keeps -plate S0 from falling out between adjacent bricks after the adhesive layer has melted and before the plate is retained in place due to the reaction between the plate and the refractory material of the brick.

Plate 50 is provided with iirst embossment means at the lower end thereof adjacent the hot end face of the refractory body, this embossment means comprising a plural-ity of integral outwardly extending embossments which are substantially circular in configuration. These embossments are shown as comprising a lower row of four embossments and an upper staggered row of three embossments. It is apparent that these embossments may be arranged in a different manner and any number of embossments may be employed as required in any desired array. In any event, the embossment means is formed at the lower portion of the plate and obviously occupies only a very minor portion of the overall face area ofthe plate. The embossments 80 are of identical construction with the other embossments of the plate hereinafter described.

Plate 50 also includes second embossment means formed at an intermediate portion of the plate and comprising a plurality of integral outwardly extending embossments S2 similar to embossments 80 and arranged in a similar manner except that the row of four embossments is disposed over the row of three embossments. Here again, the embossments have a substantially circular appearance as seen in elevation, and as illustrated in FIG. 4 have a cross sectional dimension wherein sloping wall portions 82 connect the outer wall portion of each of the embossments with the material of the plate 50, the outer wall portion of the embossments being disposed substantially parallel with the flat plate. It is accordingly lapparent that these embossments will provide flat outer bearing surfaces which are parallel with the plate 50 and which extend out of the plane thereof for spacing the adjacent refractory brick away from the associated plate.

Plate 52 has the lower edge 90 thereof spaced upwardly from the hot end arris 56 of the refractory body, while the opposite side edges 92 and 94 of plate 52 are spaced inwardly from the longitudinally extending arrises 60 of the body. The top edge 96 of plate 52 is also spaced slightly below the hot end arris 66 of the refractory body.

Plate 52 is provided w-itha first plurality of integral outwardly extending embossments 100 disposed at the lower end thereof adjacent the hot end face of the refractory body. These embossments also may be of various number and array and are illustrated as including four lower embossments and two embossments disposed thereabove and spaced from oneanother. Plate 52 also includes second embossment means in the form of a plurality of integral outwardly extending embossments 102 formed in lthe upper portion of the plate adjacent the cold end face of the refractory body, these embossments also including a first row of four embossments and a pair of embossments disposed therebelow.

A first integral indentation 110 is formed in plate 52 between the pair of upper embossments 100 in the plate, and a second integral inwardly extending indentation 114 is disposed between the pair of lower embossments 102 at the other end of the plate. These indentations 110 and 114 are adapted to fit within recesses 112 and 116 respectively provided at the lower and upper portions of the refractory body and being formed in the face 36 thereof. The intercooperation between the indentations and the recesses is such as to assure proper alignment of plate 52 on the lateral face of the brick and to ensure stability of such plate on the associated face. In other words, it is clear that the intercooperation between the indentations and the recesses will enable the plate S2 to be properly aligned on the face when initially adhesively securing the plate to the face, and in addition upon firing of the furnace, the cooperation between the indentations and the associated recesses will serve to maintain the plate 52 in proper -operative position. This intercooperation is necessary even though the plates 52 are normally under compression between the adjacent laterally extending row of bricks.

The configuration of the integral embossments formed on the plates is such as to provide adequate strength to support the roof when it is initially assembled, and at the same time the embossments are designed to collapse on heating to provide for radial thermal expansion at both the hot and cold faces of the brick. These embossments also provide proper end-to-end expansion relief. While the embossments have been illustrated as being generally circular, attention is directed to FIG. 8 of the drawings wherein a modification is illustrated. As seen in this figure, a refractory body 12) is provided with a plate 122, these components corresponding tomernbers 30 and S2 for example in the previously described modiiication. In this instance, plate 122 is provided with embossments 124 which may be substantially square. Accordingly, it is apparent that the shape of the embossments is not restricted to any particular configuration, but it is desired to provide a plurality of spaced embossments in each case in a particular area of the plate in order 4to accomplish the desired end results.

As seen particularly in FIG. 3, the cold end face 40 of the refractory body is provided with an indicating means identified by reference character for indicating the key direction and to permit rapid orientation of the refractory unit in a roof ring. The indicating means in this particular case takes the form of an arrow which points in the lateral direction of the roof. It is apparent that a bricklayer will immediately be advised as to the lateral direction of the roof simply by glancing at this indicating arrow provided on the cold end face of the brick. This indicating means may either be stencilled on the cold end face or formed integrally therein if desired.

Referring now particularly to FIG. 2 of the drawings, the rnanner in which the refractory brick units of the present invention are assembled is illustrated. In this particularillustration, it is assumed that a plurality of identical units 30 will be employed in side-by-side relationship with one another. It is `apparent that in the assembled relationship as illustrated, the units are so oriented that they are disposed in similar relationship to one another whereby a plate is disposed between adjacent faces of each of the refractory bodies so that the metallic material will be adapted to react rwith the refractory bodies to form a substantially impervious solid rigid shell about each of the refractory bodies upon tiring of the furnace. It is also apparent that the embossments on each of the plates provide a space between the plates secured to one of the refractory bodies and the adjacent unplated surface of another refractory body. This, of course, permits the heat to rise up between the adjacent refractory bodies. The spacing of the longitudinal edges of the various plates from the longitudinally extending arrises of the refractory bodies also provide tunnels indicated by reference numerals 134 through which the heat may rise upon initial tiring of the furnace to provide a more uniform distribution of the heat along the length of the units.

Referring now particularly to FIG. 7 of the drawings, a vertical section is shown through two laterally extending rows of bricks of different length, refractory body 30 being identical with the refractory body 3@ previously described and having the plates disposed thereon according to the previous description. This refractory unit is adapted to be positioned adjacent a refractory unit of greater length and including a refractory body which in all other respects is similar in construction to refractory body 30 except for the fact that it is of greater length.

Refractory body 140 is provided with a plate .142 which is similar to the plate 50 previously described and it is adhesively secured to the associated face of the refractory body by means of a thin layer 144 of adhesive material. Plate 142 also includes an integral tab 146 which is similar to the tab 72 previously described. It will be understood that refractory body 140 is also provided with a pla-te corresponding to the plate 52 previously discussed.

Plate 142 is provided with a loiwer plurality of ernbossments `15() corresponding to the embossments 80 previously described, and an upper plurality of embossments 152 are provided and which are similar in number and array to the embossments 82 provided on plate 50.

The spacing of the embossments 152 from the embossments is identical with the spacing of the embossments 80 with respect to the embossments 82 as previously described. Accordingly, when bricks of diterent length are disposed adjacent to one another, as illustrated in FIG. 1 wherein a first plurality of rows 22 of bricks of a certain length are positioned adjacent to a second plurality o-f rows 24 of bricks of a greater length, the bearing between the bricks as occasioned by the contact of the upper and lower embossment means in the plates of the longitudinal faces of the bricks will be at a common location regardless of the length of the brick. On the other hand, the embossment means formed at the upper portion of the plate on the lateral face of the longer bricks may be disposed adjacent the cold end face of the bricks sov that -these embodiments are not necessarily spaced from the lower embossment means the same distance as is the case with a shorter brick. The similar spacing of the upper and lower embossment means is desirable on the longitudinal faces of the bricks since the shorter bricks and the longer bricks have bearing surfaces along such longitudinal faces. On the other hand, the lateral faces of the various bricks only have common bearing relationship with bricks of the same length.

It is apparent from the foregoing that there is provided according to the present invention a new and novel refractory brick and furnace construction wherein the individual bricks are provided with steel plating means on only two adjacent faces of the brick. The steel plates are provided with integral outwardly extending embossments which are strong enough to support the roof prior to firing and which are adapted to collapse upon heating of the roof to 'provide for radial thermal expansion and to provide proper end-to-end expansion relief. The spacing of the embossments provided on the plates on the longitudinal faces of the bricks is the same regardless of the length of the bricks so as to provide `a bearing relationship at a common location on bricks of different sizes. The plate provided on the longitudinal face of each refractory body is provided with an integral tab means to hold the plate in place and properly aligned during firing of the furnace and prior to bond-ing of the material of the plate to the refractory body. The plate provided on the lateral face of each refractory body is provided with means in the form of indentations and cooperating recesses for providing proper alignment of the plate on the associated face and stability of the plate on such face. Indicator means is also provided on the cold end face of the refractory body so as to show the key direction and to provide a means for rapidly orienting the brick for installation in a roof ring.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the in- Vention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

I claim:

1. In a furnace roof construction, a plurality of refractory brick units, each of said units including a pair of opposite longitudinal faces facing longitudinally of the roof and a pair of opposite lateral faces facing laterally of the roof, each of said units including a hot end face adapted to be positioned in facing relationship to the interior of a furnace and a cold end face remote from said hot end face, the lateral faces of adjacent units being in side-by-side relationship and the longitudinal faces of adjacent units being in side-by-side relationship, a first plurality of units extending laterally of a roof and being of a certain length, a second plurality of units extending laterally of a roof and being of a greater length than said first plurality of units, the longitudinal faces of the first plurality of units being disposed adjacent the longitudinal faces of said second plurality of units, each of said units having metallic plates fixedly secured only to one longitudinal face thereof and one adjacent lateral face thereof, means for properly aligning and retaining each of said plates secured to each unit in the proper relative relationship on the associated face of the unit, each of said plates of each unit including first embossment means formed in the plate adjacent the hot end arris of the associated face, each of said plates also including second embossment means formed in the plate in a location spaced away from said first embossment means in a direction toward the cold end arris of the associated face, the second embossment means of the plate on the lateral face of each of said units being formed adjacent the cold end arris of the associated face,

the second embossment means formed in the plate disposed on the longitudinal face of each of said bricks being disposed at an intermediate position of such plate, and the said second embossment means on the plates of the longitudinal faces of said first plurality of bricks being spaced from the first embossment means of such plates a distance which is the same as the spacing of the second embossment means of the second plurality of plates from the first embossment means of the second plurality of plates on the longitudinal faces of said second plurality of plates whereby the bearing between the longitudinal faces of the bricks is at a common location regardless of the length of the bricks.

2. A refractory brick unit for use in the construction of a roof of a furnace comprising a body of refractory material having a pair of opposite longitudinal faces adapted to face longitudinally and extend circumferentially of the roof and a pair of opposite flat lateral faces adapted to face laterally of the roof, said body also -including a hot end face adapted to be positioned in facing relationship to the interior of a furnace and an opposite cold end face remote from said hot end face, said body having a substantially square configuration at the cold end portion thereof and being slightly out of square at the hot end portion thereof, flat metallic plate means secured only to one longitudinal face of said brick and to one adjacent lateral face of said brick, the plate means on said longitudinal face of the body having a first plurality of integral embossments extending outwardly therefrom and formed in the plate means adjacent the hot end arris of the associated face, and also having a second plurality of integral outwardly extending embossments formed therein and being disposed at an intermediate position of such plate, the plate means on said lateral face of the body having a first plurality of integral embossments extending outwardly therefrom and formed in the plate means adjacent the hot end arris of the associated face, and also having a second plurality of integral outwardly extending embossments formed therein and spaced in relationship to said first plurality of embossments adjacent the cold end arris of the associated face of the brick.

3. Apparatus as defined in claim 2 vwherein the plate means adjacent said longitudinal face of the body has an integral tab extending from the upper end thereof and extending over and being in contact with the upper cold end of the body, the plate means adjacent the lateral face of the body having an indentation formed therein, said last-mentioned lateral face of the body having a recess formed therein for receiving the indentation for positively aligning the plate means on the last-mentioned lateral face of the body.

4. A furnace for the making of steel and the like having a curved surface such as an arched roof made up of a plurality of refractory brick units of magnesiabearing refractory material substantially square in crosssection at their cool end farthest from the furnace lying in a range from 3" x 3 to 31/2 x 31/2 and at the hot end nearest the furnace the same size longitudinally of the arch but slightly less in width laterally of the arch, each of said units having a separate steel plate secured only to one longitudinal face thereof and one adjacent lateral face thereof, each of the plates secured to a longitudinal face of a unit having an integral tab formed at the upper end thereof which rests upon the upper surface of the associated unit, each of the plates secured to a lateral face of a unit including with the lateral face of the unit interengageable alignment means for properly aligning and stabilizing such plate on the face of the brick, each of the plates on each unit including a first plurality of integral embossments extending outwardly therefrom and formed in the plates adjacent the hot end arris of the associated face, and each of said plates also including a plurality of inte- 9 gral outwardly extending embossments formed in the said plates in spaced relationship to said rst plurality of embossments toward the cold end arris o-f the associated faces of the brick, said second plurality of embossments formed in the plate on a lateral face of each unit being disposed adjacent the cold end arris of the associated face, and the second plurality of embossments formed in a plate on a longitudinal face of each unit being disposed at an intermediate point of the associated plate.

References Cited by the Examiner UNITED STATES PATENTS Hall 110-99 Grith 110-99 X Rochow 110-99 Mason et al. 110-99 Samuel et al. 110-99 Palacio 110-99 A 10 FREDERICK KETTERER, Primary Examiner. 

1. IN A FURNACE ROOF CONSTRUCTION, A PLURALITY OF REFRACTORY BRICK UNITS, EACH OF UNITS INCLUDING A PAIR OF OPPOSITE LONGITUDINAL FACES FACING LONGITUDINALLY OF THE ROOF AND A PAIR OF OPPOSITE LATERAL FACES FACING LATERALLY OF THE ROOF, EACH OF SAID UNITS INCLUDING A HOT END FACE ADAPTED TO BE POSITIONED IN FACING RELATIONSHIP TO THE INERIOR OF A FURNACE AND A COLD END FACE REMOTE FROM SAID HOT END FACE, THE LATERAL FACES OF ADJACENT UNITS BEING IN SIDE-BY-SIDE RELATIONSHIP AND THE LONGITUDINAL FACES OF ADJACENT UNITS BEING IN SIDE-BY-SIDE RELATIONSHIP, A FIRST PLURALITY OF UNITS EXTENDING LATERALLY OF A ROOF AND BEING OF A CERTAIN LENGTH, A SECOND PLURALITY OF UNITS EXTENDING LATERALLY OF A ROOF AND BEING OF A GREATER LENGTH THAN SAID FIRST PLURALITY OF UNITS, THE LONGITUDINAL FACES OF THE FIRST PLURALITY OF UNITS BEING DISPOSED ADJACENT THE LONGITUDINAL FACES OF SAID SECOND PLURALITY OF UNITS, EACH OF SAID UNITS HAVING METALLIC PLATES FIXEDLY SECURED ONLY TO ONE LONGITUDINAL FACE THEREOF AND ONE ADJACENT LATERAL FACE THEREOF, MEANS FOR PROPERLY ALIGNING AND RETAINING EACH OF SAID PLATES SECURED TO EACH UNIT IN THE PROPER RELATIVE RELATIONSHIP ON THE ASSOCIATED FACE OF THE UNIT, EACH OF SAID PLATES OF EACH UNIT INCLUDING FIRST EMBOSSMENT MEANS FORMED IN THE PLATE ADJACENT THE HOT END ARRIS OF THE ASSOCIATED FACE, EACH OF SAID PLATES ALSO INCLUDING SECOND EMBOSSMENT MEANS FORMED IN THE PLATE IN A LOCATION SPACED AWAY FROM SAID FIRST EMBOSSMENT MEANS IN A DIRECTION TOWARD THE COLD AND END ARRIS OF THE ASSOCIATED FACE, THE SECOND EMBOSSMENT MEANS OF THE PLATE ON THE LATERAL FACE OF EACH OF SAID UNITS BEING FORMED ADJACENT THE COLD END ARRIS OF THE ASSOCIATED FACE, THE SECOND EMBOSSMENT MEANS FORMED IN THE PLATE DISPOSED IN THE LONGITUDINAL FACE OF EACH OF SAID BRICKS BEING DISPOSED AT AN INTERMEDIATE POSITION OF SAID PLATE AND THE SAID SECOND EMBOSSMENT MEANS ON THE PLATES OF THE LONGITUDINAL FACES OF SAID FIRST PLURALITY OF BRICKS BEING SPACED FROM THE FIRST EMBOSSMENT MEANS ON SUCH PLATES A DISTANCE WHICH IS THE SAME AS THE SPACING OF THE SECOND EMBOSSMENT MEANS OF THE SECOND PLURAITY OF PLATES FROM THE FIRST EMBOSSMENT MEANS OF THE SECOND PLURALITY OF PLATES ON THE LONGITUDINAL FACES OF SAID SECOND PLURALITY OF PLATES WHEREBY THE BEARING BETWEEN THE LONGITUDINAL FACES OF THE BRICKS IS AT A COMMON LOCATION REGARDLESS TO THE LENGTH OF THE BRICKS. 